1. Field of the Invention
The present invention relates to a cylinder head with a water jacket, of a water-cooled internal combustion engine to be mounted on motor vehicles, and a method of manufacturing the cylinder head.
2. Description of the Related Art
Some type of water-cooled internal combustion engines are mounted on a motor vehicle in a longitudinal position with the crankshaft thereof extended longitudinally of the vehicle and some other type of water-cooled internal combustion engines are mounted on a motor vehicle in a transverse position with the crankshaft thereof extended transversely of the vehicle. Flow of cooling water in the cylinder head of an internal combustion engine dominates the mode of installation of the internal combustion engine in a vehicle; that is, an internal combustion engine designed for longitudinal installation cannot be transversely installed, and vice versa.
A water-cooled internal combustion engine is cooled by an intake preferential cooling system that controls the flow of cooling water in the cylinder head so that intake air is cooled preferentially to achieve a high compression ratio to suppress knocking or by an ordinary cooling system. Flow of cooling water in such an internal combustion engine limits the installing position of the engine to either of longitudinal and transverse installing positions.
A prior art cylinder head has a water jacket provided with a plurality of cooling water exit openings, one of which is used selectively for the cooling system (see JP-2001-107729 A). The cylinder head of such construction reduces the manufacturing cost of the cylinder head.
The plurality of cooling water exit openings of this previously proposed cylinder head disclosed in JP-2001-107729 A are formed during the manufacture of the cylinder head. Some of the cooling water exit openings are plugged up with detachable plugs and the rest are left open to form a desired flow of cooling water in the cylinder head.
This prior art cylinder head needs plugs or covers to block up some of cooling water exit openings and sealing members for water-tight blocking of the cooling water exit openings. Consequently, the cylinder heads needs additional parts and troublesome blocking work. Formation of the plurality of cooling water exit openings during the manufacture of the cylinder head needs many man-hours for machining and increases the manufacturing cost.